Hey Roger that is interesting 
- 501880 used is not bad especially compared to ubuntu-16 at 729592… Old HP G60 at 386000…! @easyt50 Howard has many posts showing LIGHT distros (with supposed LIGHT DE’s) slightly heavier on resources than full Trisquel…
By the way the reason I use that gnulinux web page video for testing isn’t because I’m an addict but it is something everyone can access without the complexities, cookies and scripts of YTube thus providing a level playing field for comparisons. FsF and gnulinux web pages do not use cookies thereby exposing the lie of strictly necessary cookies of other web sites - it’sFOSS included…!
I have not used Kubuntu myself but plenty here at it’sFOSS do use it. Trust you are not using KDE…? I am thinking of taking a quick full installation look at mini-Trisquel on the Dell as I am soon to BleachBit or Format the Dell’s SSD as I have now tested the full monty v9 and have the HP Notebook as my everyday workhorse.
Yes - we both know it does not work - h-node org confirms this…
So did you look at the Think-Penguin dot com Wifi section …? I don’t need Wifi really but would be sure to check out their stuff first as it is tested and guaranteed to work. Think I will raise a Topic on this hardware issue as many people at it’sFOSS seem to have blinkers on when it comes to gnulinux - pity; as the solution is soooooooo easy… 
https://www.thinkpenguin.com/gnu-linux/penguin-wireless-n-usb-adapter-gnu-linux-tpe-n150usb
Some photos and specs from an old article may be of interest…?
It’sFOSS - calling international rescue 
hope all this helps with your quest(s) 